The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
DC-DC converters may be used to perform step-down power conversion. For example, DC-DC converters may be used in electronic systems requiring high-quality, low DC voltages to supply sensitive integrated circuits. Applications such as central processing units (CPUs) or graphics processing units (GPUs) may require low voltages around 1 V DC. The DC-DC converters may include a buck converter with a high-side switch, a low-side switch, an inductance, and an output capacitance. The switching frequency and the sizes of the switches, inductance, and output capacitance are optimized for a particular application.
After the high-side switch is opened, the stored energy in the inductance flows to the output capacitance (and load) as dictated by the LC resonance cycle of the inductance and the output capacitance, and by the characteristics of the load. The peak output voltage is a direct result of the continuous current in the inductance necessarily flowing into the output capacitance and load. The load must be able to withstand the peak output voltage.
The value of the inductance is usually kept relatively low to limit stored energy, inductor site, and winding copper loss. Limiting stored energy is one way to limit the increase in the output voltage so as to not adversely impact the reliability of the load. However, the low inductance value requires a high converter switching frequency in order to prevent inductance saturation and to limit ripple current. Higher switching frequency tends to increase converter switching losses and lower overall efficiency.